Active scanner bow compensator

Abstract

An active scanner bow compensator for use with a scanner is described. The scanner includes a moveable scanning platform supported within a frame. The active scanner bow compensator supports the scanner and includes a frame of reference, sensors, and an actuator. The sensors detect out-of-plane motion of the scanning platform relative to the frame of reference, and the actuators compensate for the out-of-plane motion by adjusting the orientation of the frame relative to the frame of reference. The active scanner bow compensator may be used in atomic force microscopy applications.

What is claimed is: 
     
       1. A device for compensating for out-of-plane motion comprising:
 a scanner including:
 a scanning platform; and 
 a frame defining X and Y axes of a first plane and supporting the scanning platform, wherein the scanning platform is moveable relative to the frame along the X axis, the Y axis, or the X and Y axes of the first plane; and 
 
 a compensator including:
 a frame of reference defining X and Y axes of a second plane; 
 a sensor that detects out-of-first-plane motion of the scanning platform; and 
 an actuator operationally connected to the sensor that changes orientation of the first plane relative to the second plane to compensate for the out-of-first-plane motion of the scanning platform detected by the sensor. 
 
 
     
     
       2. The device of  claim 1  wherein the sensor is disposed between the frame of reference and the scanning platform. 
     
     
       3. The device of  claim 1  wherein the frame of reference has a top surface, the scanning platform has a bottom surface that is at least partially exposed while being supported by the frame, and the sensor contacts the top surface of the frame of reference and the bottom surface of the scanning platform. 
     
     
       4. The device of  claim 1  wherein the actuator is disposed between the frame of reference and the frame. 
     
     
       5. The device of  claim 1  wherein the frame of reference has a top surface, the frame has a bottom surface, and the actuator contacts the top surface of the frame of reference and the bottom surface of the frame. 
     
     
       6. The device of  claim 1  wherein the compensator comprises an array of sensors and an array of actuators. 
     
     
       7. The device of  claim 6  wherein the array of sensors comprises at least three sensors and the array of actuators comprises at least three actuators. 
     
     
       8. The device of  claim 1  wherein the actuator is a piezoelectric actuator. 
     
     
       9. The device of  claim 1  wherein the sensor is a capacitive sensor. 
     
     
       10. The device of  claim 1  further comprising a controller operationally connecting the sensor and the actuator, wherein the controller receives positional information from the sensor and delivers an input signal to the actuator and wherein the input signal induces the actuator to change the orientation of the first plane relative to the second plane to compensate for the out-of-first-plane motion of the scanning platform. 
     
     
       11. The device of  claim 1  further comprising a mounting support connecting the frame of reference to the frame, wherein the mounting support is substantially moveable only in an axis orthogonal to the second plane such that the mounting support inhibits translational motion of the frame relative to the frame of reference along either the first or second planes. 
     
     
       12. The device of  claim 1  wherein the scanning platform is moveable in both the X and Y axes of the first plane. 
     
     
       13. A method of compensating for out-of-plane motion with a device as recited in  claim 8  comprising:
 supporting the scanner on the compensator; 
 detecting out-of-first-plane motion of the scanning platform with the sensor; and 
 adjusting orientation of the first plane relative to the second plane with the actuator, wherein the adjusting substantially compensates for the out-of-first-plane motion of the scanning platform detected by the sensor. 
 
     
     
       14. The method of  claim 13  wherein the sensor is disposed between the frame of reference and the scanning platform. 
     
     
       15. The method of  claim 13  wherein the sensor contacts a top surface of the frame of reference and a bottom surface of the scanning platform. 
     
     
       16. The method of  claim 13  wherein the actuator is disposed between the frame of reference and the frame. 
     
     
       17. The method of  claim 13  wherein the actuator contacts a top surface of the frame of reference and a bottom surface of the frame. 
     
     
       18. The method of  claim 13  wherein the sensing is performed by an array of sensors and the adjusting is performed by an array of actuators. 
     
     
       19. The method of  claim 18  wherein the array of sensors comprises at least three sensors and the array of actuators comprises at least three actuators. 
     
     
       20. The method of  claim 13 , further comprising operationally connecting the sensor and the actuator with a controller, wherein the controller receives positional information from the sensor and delivers an input signal to the actuators and wherein the input signal induces the actuator to change the orientation of the first plane relative to the second plane to compensate for the out-of-first-plane motion of the scanning platform. 
     
     
       21. The method of  claim 13  wherein the supporting includes connecting a mounting support between the frame of reference and the frame, wherein the mounting support is substantially moveable only in an axis orthogonal to the second plane such that the mounting support inhibits translational motion of the frame relative to the frame of reference along either the first or second planes. 
     
     
       22. The method of  claim 13  comprising reducing the out-of-first-plane motion of the scanning platform to no greater than 2 nm per 100 μm of scanning range.